Due to the tremendous volume of mail processed daily in the United States and other countries, mail sorting equipment has become increasingly complex. Sophisticated scanning equipment along with computer controlled high speed conveying and sorting machines are used to process an ever increasing volumes of postcards, letters, magazines, parcels and other types of mail. With the added complexity has come increased difficulty in troubleshooting timing problems, mechanical component problems, sensor problems, functional problems and problems due to component wear prior to down-time events created by component failure. Unscheduled down-time is increasingly costly due to higher customer expectations regarding timely delivery and high throughput processes. Component failure can create processing errors (i.e., operation at reduced effectiveness) or create unscheduled down-time which halts production until repairs are made.
Mail processing facilities and equipment are necessarily designed having areas for which access must be restricted during processing. For example, letter processing machines have interlocked doors and covers such that run-time access is prohibited for safety and security reasons. Many areas within machines and systems cannot be viewed during operation. Additionally, in large material handling systems, it is simply not practical to provide operator access to all areas of the system.
Mail processing machinery design has generally not kept pace with technological advances in the area of on-board diagnostics and self-test capability. The level of technical skill required to troubleshoot the equipment has increased. In at least some markets, qualified maintenance and operations personnel are not available. Troubleshooting is presently a costly manual task requiring highly trained personnel. In many cases, troubleshooting involves trial and error strategies which are inefficient.
A fundamental issue related to high volume processing operations is the conflict between the desire to operate a machine and the need to halt the machine to perform needed maintenance and troubleshooting functions. Generally, maintenance managers must negotiate time with production or operations management for down-time in which to perform needed repairs. There is an element of risk that if a machine is taken down for troubleshooting and repair, it may not be available for the next processing cycle. In many cases, troubleshooting the problem requires more time than the actual repair, once the problem is known.
Costs associated with repairing machinery during scheduled down-time are inherently lower than costs associated with repairing a machine during production time. Therefore, preventive maintenance activities which identify and eliminate timing problems, failed components, or components in a state of wear which are likely to fail during the next operation interval save costly downtime.